Tonneau cover rail retaining mechanism

ABSTRACT

A tonneau system for a cargo box of a vehicle including a support frame, a cover spanning the support frame; and a clamp. The support frame includes side rails having an inboard section and an outboard section, such that the outboard section is positioned adjacent to the top surface of the sidewall of the cargo box to aid in the supporting and positioning of the support frame. The clamp is capable of hanging from the support frame during installation to improve the ease thereof. The clamp also includes a pair of members being positionable in any one of a plurality of discrete positions for improved installation. A front rail adjustment mechanism permits the selective tensioning of the cover to maintain a predetermined load therein. While a front rail retaining mechanism is slidably coupled to the front rail member to prevent the front rail member from being inadvertently disengaged from the side rail members. A rear rail retaining mechanism is used to lock the rear rail member or unlock the rear rail member and urge the rear rail member upward.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional application of U.S. patent applicationSer. No. 10,331,711, filed Dec. 30, 2002, now U.S. Pat. No. 6,752,449.The disclosure of the above application is incorporated herein byreference.

FIELD OF THE INVENTION

The present invention generally relates to coverings for pickup trucksand, more particularly, relates to a roll up tonneau cover system.

BACKGROUND OF THE INVENTION

Tonneau covers have been used for a number of years to cover the cargobox of pickup trucks against dirt, debris, and other environmentalcontaminants and to improve the aesthetic quality thereof. Originally,tonneau covers were designed by upholstery shops and typically made ofvinyl covered fabrics or canvas. The material was often doubled overalong its edges for added strength and appearance. Male snaps were thenattached to the sides of the cargo box of the pickup truck viafasteners, while female snaps were attached along the edges of thecover. Wooden bows were sometimes used to span the cargo box and ensurethat the cover remained high enough to drain water. Unfortunately, thesecovers were sometimes difficult to handle, often led to corrosion aroundthe snaps, and occasionally failed to protect the cargo box.

However, in the '70's, in an attempt to overcome the corrosion aroundthe snaps, tonneau rails were removably mounted to the cargo box of thepickup truck using clamps. These tonneau rails carried theaforementioned snaps and, thus, eliminated the need to mount the snapsdirectly to the walls of the cargo box.

With the advent of the VELCRO® hook-and-loop fastening system, tonneaucover systems were developed that included gluing one of the hook orloop strips to the pickup truck and sewing the other strip to the fabrictonneau cover material to effect a simple connection without alteringthe vehicle body. An example of this system is shown in U.S. Pat. No.4,272,119, issued to Adams. The disclosure of which is herebyincorporated and made a part of this application by reference. However,the tonneau cover of Adams had a problem remaining attached near thefront of the cargo box, most likely due to wind forces. This problem wasovercome using a rod of stiff rope or fiberglass sewn into a flap alongthe front of the tonneau cover. This rod was received within a channelhaving a “bite” mounted near the front of the cargo box to retain thetonneau cover in an attached position.

Rotating rails were later developed to fasten and tighten a tonneaucover. One such system employed two side rails running longitudinallydown the sides of the cargo box of the pickup vehicle. A second rail waspivotally attached to each of the two side rails and carried the fabrictonneau cover such that upon downward rotation of the second rails, thefabric tonneau cover was pulled tight. The second rails were then lockedin connection with the side rails. This system further included VELCRO®fasteners along the front and rear edges and a zipper for separatingleft and right halves. An example of this system can be seen in U.S.Pat. No. 4,036,521, issued to Clenet. The disclosure of which is herebyincorporated and made a part of this application by reference.

Similar to the above system, a tongue and groove connector system isalso known for detachably fastening a stretchable fabric panel to arigid frame. The tongue and groove connector system included atongue-forming element attached along a line intermediate the side edgesthereof to the stretchable fabric panel. The tongue being insertableinto a groove with a projecting portion extending there beyond whichdefines a handhold. The connection requires the fabric to be stretchedto a point where the leading edge of the tongue lies adjacent theentryway into the groove such that the stretched fabric pulls the tongueinto seated relation in the bottom of the groove. An example of thissystem can be seen in U.S. Pat. No. 4,757,854, issued to Rippberger. Thedisclosure of which is hereby incorporated and made a part of thisapplication by reference.

Similarly, the convertible boot cover for the 1980 FORD® Mustangincludes a trim strip around a boot having a slot for inserting apolymer tongue that is sewn to the cover. The tongue is toggled into theslot providing an attachment for the cover. This attachment is similarto that of Rippberger '854.

Further development of tonneau systems led to the use of 45° angledframe rails to improve the aesthetic quality of the tonneau cover. Theangled frame rails carried a snap connector for retaining the tonneaucover material. Often, these systems included a double layer of tonneaucover material in the region of the snaps for added reinforcement. Suchsystems also included a clamp system for coupling with the sidewalls ofthe cargo box. One such clamp system used a clamp that “bottomed out” toprevent over stressing the sidewalls of the cargo box. Examples of thesesystems can be seen in U.S. Pat. Nos. 4,730,866 and 4,838,602, issued toNett. The disclosures of which are hereby incorporated and made a partof this application by reference.

Many of these previous features were incorporated in later designs withslight modifications. For example, U.S. Pat. No. 5,076,338, similar toU.S. Pat. No. 4,036,521, employed a pivoting rail to tighten the tonneaucover material. In this particular system, an “L” shaped rail, whichpresumably puts the pivot lower for added mechanical advantage, was usedto tighten the tonneau cover material from a fore and aft position,rather than cross-car position. This system further employed the 45°angled frame rails and VELCRO® fasteners. The frame rails are coupled tothe sidewalls of the cargo box using a plurality of C-clamps.Furthermore, the system included a double layer of tonneau covermaterial in the region of the snaps for added reinforcement as seen inprevious designs.

In a more recent design, a rotating rear rail was provided that includedpositioning the pivot near the upper surface of the tonneau to minimizetorque exerted on the rear rail. The lower torque of this systempermitted the use of relatively lightweight plastic levers to lock therear rail and prevent it from rotating. The combination of the length ofthese plastic levers and high pivot locations enabled the loads exertedon the levers to be about {fraction (1/12)}th that of the tonneau covermaterial. Springs were also taught that enabled the automatic tensioningof the tonneau cover material. An example of this system can be seen incommonly owned U.S. Pat. No. 5,251,951, issued to Wheatley. Thedisclosure of which is hereby incorporated and made a part of thisapplication by reference.

Relatively recently, a tonneau cover system having a screw adjustmentmechanism was developed for permitting the fore and aft adjustment ofthe front rail. This screw adjustment mechanism serves to tighten thetonneau cover material in response to wear and/or stretch that is commonin tonneau cover systems. The tonneau cover system further employed the“L” shaped lever and lower-positioned pivot, which unfortunatelyrequires the lever to carry an enormous amount of force. That is, by wayof example, assuming a 1″ thick rail with a ½″ offset to the latchingpivot, a 30-pound-tarp load will impart a 60-pound load on the lever.Consequently, a stronger latch is required to overcome these loadingforces and minimize wear and breakage. Frame rails are coupled to thesidewalls of the cargo box using a plurality of C-clamps. An example ofthis system can be seen in U.S. Pat. No. 5,906,407, issued toSchmeichels. The disclosure of which is hereby incorporated and made apart of this application by reference.

A TRUXEDO cover, which is not believed to be patented, made by SHURCOincludes a rotating, rectangular, rear rail having a rounded frontpivot, vertical sides with VELCRO® attachment, and spring pins that pushon a front rail mounted inboard of the side rails. These spring pinspush against the front rail to tension the system in the fore-aftdirection. The spring pins, which are attached to the side rails viabrackets, may not firmly engage the front rail due to their inboardlocation which may cause the brackets to come out of alignment as theside rails rotate. Additionally, the rounded shape of the front railsmay cause the push pins to slip off-center.

Lastly, U.S. Pat. No. 6,293,608, issued to Dicke, et al., discloses atailgate rail interconnected to side rails with an interconnecting platefixedly coupled to the side rails and slideably coupled to the cornerpiece for accommodating relative movement therebetween. A biasingdevice, being a coil spring, is further provided. This system providestensioning to the tonneau fabric.

SUMMARY OF THE INVENTION

According to the principles of the present invention, a tonneau systemfor a cargo box of a vehicle having an advantageous construction isprovided. The tonneau cover system includes a support frame, a coverspanning the support frame, and a clamp. The support frame includes siderails having an inboard section and an outboard section, such that theoutboard section is positioned adjacent to the top surface of thesidewall of the cargo box so as to aid in the supporting and positioningof the support frame. The clamp is capable of hanging from the supportframe during installation to improve the ease thereof. The clamp alsoincludes a pair of members being positionable in any one of a pluralityof discrete positions for improved installation. A front rail adjustmentmechanism permits the selective tensioning of the cover to maintain apredetermined load therein. While a front rail retaining mechanism isslidably coupled to the front rail member to prevent the front railmember from being inadvertently disengaged from the side rail members. Arear rail retaining mechanism is used to lock the rear rail member orunlock the rear rail member and urge the rear rail member upward.

Further areas of applicability of the present invention will becomeapparent from the detailed description provided hereinafter. It shouldbe understood that the detailed description and specific examples, whileindicating the preferred embodiment of the invention, are intended forpurposes of illustration only and are not intended to limit the scope ofthe invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will become more fully understood from thedetailed description and the accompanying drawings, wherein:

FIG. 1 is a perspective view illustrating a pickup truck having atonneau cover system according to the principles of the presentinvention;

FIG. 2 is a cross sectional view illustrating the frame rail assemblytaken along line 2—2 of FIG. 1;

FIG. 3 is a plan view illustrating the front rail member and frame railassembly;

FIG. 4 is a partial cross sectional view illustrating the front railmember and frame rail assembly taken along line 4—4 of FIG. 3;

FIG. 5 is a partial cross sectional view illustrating the front railmember and frame rail assembly taken along line 5—5 of FIG. 3;

FIG. 6 is a perspective view illustrating the retaining mechanism;

FIG. 7 is a partial cross sectional view illustrating the rear railmember and frame rail assembly shown in a locked position;

FIG. 8 is a partial cross sectional view illustrating the rear railmember and frame rail assembly shown in an intermediate position; and

FIG. 9 is a partial cross sectional view illustrating the rear railmember and frame rail assembly shown in an unlocked and upwardly urgedposition.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The following description of the preferred embodiments is merelyexemplary in nature and is in no way intended to limit the invention,its application, or uses.

With reference to FIG. 1, a pickup truck 10 is shown having a roll uproll up tonneau system 12 which is attached to a cargo box 13 accordingto the present invention. Cargo box 13 has a front wall 14, a leftsidewall 16, a right sidewall 18, and a rear wall or tailgate 20. Rollup roll up tonneau system 12 includes a flexible, stretchable fabriccover 22 that is drawn tightly over a substantially rigid rail supportsystem 24 and removably attached to rail support system 24. Rail supportsystem 24 is comprised of a number of frame rails that are attached toone another to form a rectangular frame. The frame rails included are afront frame rail or head rail assembly 26, a left side frame railassembly 28, a right side frame rail assembly 30, and a rear frame railassembly 32. Rail support system 24 is aligned with the top of sidewalls16 and 18 of cargo box 13 as well as the top of front wall 14 andtailgate 20.

It should be understood that right sidewall 18 and left sidewall 16 ofpickup truck 10 and the corresponding right side frame rail assembly 30and left side frame rail assembly 28 are identical in construction, yetarranged in mirrored symmetry. Accordingly, in the interest of brevity,only one side will be discussed in detail below unless noted otherwise.

As best seen in FIG. 2, right side frame rail assembly 30 is coupled toright sidewall 18 of cargo box 13 of pickup truck 10. As can be seen,sidewall 18 of cargo box 13 includes a generally horizontal top surface34 and a downwardly extending inside wall 36. However, it should beappreciated that generally horizontal top surface 34 and downwardlyextending inside wall 36 may have any one of a number of configurations,which are dependent upon styling and functionality determined by thevehicle manufacturer. Hence, it should be understood that the particularshape of these surfaces/walls may vary, along with the specific shape ofthose corresponding components of frame rail assembly 30.

Still referring to FIG. 2, frame rail assembly 30 generally includes asupport bracket 38, a hanging side member 40, and a back member 42.Support bracket 38 includes a first horizontal portion 44 having achannel 46 formed therein. Channel 46 is generally defined by a pair ofupturned and inwardly projecting flanges 48. Channel 46 is sized toreceive one of a cooperating pair of strips of a hook-and-loop fastenersystem 49—that is, a first strip 50 of the pair is disposed in channel46 and the corresponding second strip 51 of the pair is mounted onfabric cover 22. Preferably, the hook-and-loop fastener system is madeof VELCRO®. However, it should be understood that alternate suitablefasteners may be used, such hook and hook material, other self-adhesivematerial, magnetic tape on steel, tongue and groove, and the like. Framerail assembly 30 further includes a downwardly extending portion 52 thatterminates into a second horizontal portion 54. Second horizontalportion 54 is adapted to support an adjustment mechanism that will bediscussed in detail below.

With continued reference to FIG. 2, frame rail assembly 30 still furtherincludes a second downwardly extending portion 56 extending from anintermediate section of first horizontal portion 44 generally adjacentinside wall 36 of sidewall 18. Second downwardly extending portion 56receives a flat seal 58 preferably adhesively coupled thereto. Flat seal58 is adapted to engage inside wall 36 of sidewall 18 to define a fluidsealing connection therebetween. Flat seal 58 may be made of anysuitable material that would at least inhibit inflow of water, dirt,debris, or other environmental contaminants.

To further prevent the influx of water, dirt, debris, or otherenvironmental contaminants from entering cargo box 13 through theinterface between support bracket 38 and sidewall 18, a second seal 60is provided. Specifically, as can be seen in FIG. 2, first horizontalportion 44 extends outboard such that an overlapping outboard section 62overlaps a portion of top surface 34 of sidewall 18 while an inboardsection 63 cantilevers inward into cargo box 13. Second seal 60 ispreferably D-shaped and extends downwardly from overlapping outboardsection 62 such that second seal 60 compressibly engages top surface 34of sidewall 18.

The overlap of overlapping outboard section 62 relative to top surface34 provides a number of useful advantages over the prior art.Specifically, such overlapping relationship between support bracket 38and sidewall 18 defines a positive positioning reference duringinstallation of roll up tonneau system 12. Additionally, the weightexerted on support bracket 38 causes second seal 60 to be furthercompressed against top surface 34 of sidewall 18, thereby furtherensuring a reliable sealing connection. Still further, the use of flatseal 58 and second seal 60 provide a double sealing connection alongboth horizontal and vertical surfaces. Unlike the prior art that sealsonly along a vertical surface, the present invention does not readilypermit water to lie upon the vertical sealing surface, whichconsiderably improves the sealing characteristics.

Turning now to the clamping system of the present invention, hangingside member 40 and back member 42 cooperate to retain support bracket 38to sidewall 18. In particular, hanging side member 40 is shown beinggenerally planar in construction with a hooked flange 64 formed on anupper end 66 and a series of alignment depressions 68 formed on anopposing end 70. Hooked flange 64 is sized to cooperate with acorresponding flange 72 extending upwardly from second downwardlyextending portion 56 so that hanging side member 40 can hang from seconddownwardly extending portion 56 during installation. Hanging side member40 further includes an aperture 73 formed therein to receive at leastone fastener 74.

Back member 42 is shown being generally U-shaped in construction havingan alignment head 76 formed on a lower end 78 and an engaging head 80formed on an upper end 82. Alignment head 76 is preferably curved inshape and sized to be received within one of the series of alignmentdepressions 68. Engaging head 80 preferably includes a pair of outwardlyextending flanges 84 adapted to retain a contact member 86. Contactmember 86 is preferably made of a soft rubber material to prevent damageto inside wall 36 of sidewall 18. However, contact member 86 is optionaland, thus, may be eliminated or replace with other material. Stillfurther, back member 42 includes a retaining nut 88 that cooperates withfastener 74 to apply a clamping force upon inside wall 36 of sidewall 18to retain support bracket 38 in position. Retaining nut 88 is preferablyheld by retaining flanges 90, which serve to hold retaining nut 88 inposition and fixed against rotation. However, it should be understoodthat other fastener systems may be used, such as a quick releaseclamping mechanism or other known means.

During clamping, back member 42 is first loosely fastened to hangingside member 40 via fastener 74 and retaining nut 88. Hanging side member40 is then conveniently inserted such that hooked flange 64 engagescorresponding flange 72 to permit hanging side member 40 and back member42 to hanging from such position. By maintaining hanging side member 40and back member 42 in a loosely fitting arrangement, back member 42 maybe positioned along a backside of inside wall 36. Back member 42 mayalso be positioned vertically relative to hanging side member 40 bymoving alignment head 76 into one of the series of alignment depressions68, thereby adjusting the position of contact member 86 upon inside wall36. In order to facilitate such adjustment, it can be seen that aperture73 formed in hanging side member 40 is preferably a slot to permit thevertical translation of fastener 74 relative to hanging side member 40.Fastener 74 is then tightened to apply a clamping force upon inside wall36 to retain support bracket 38 in position and further compress flatseal 58. It should be appreciated that the present arrangementsimplifies installation of roll up tonneau system 12 in that theclamping mechanism need not be held in place by a user with one handwhile simultaneously tightening fastener 74 with the other hand, asrequired in the prior art. Additionally, due to the hanging feature ofhanging side member 40 and overlapping outboard section 62 of firsthorizontal portion 44, frame rail assembly 30 can not be easily removedfrom pickup truck 10 nor will the clamping mechanism fall out ofposition or tonneau cover 22 drop down should fastener 74 becomeloosened.

Turning now to FIGS. 3-11, head rail assembly 26 will now be discussedin detail. As best seen in FIG. 3, head rail assembly 26 generallyincludes a forward rail member 92 that extends in the cross-cardirection generally in plane with front wall 14 of cargo box 13. Forwardrail member 92 receives an attachment member 94 coupled to fabric cover22 within a receiving channel 96 formed in an upper surface of forwardrail member 92 to define the forward edge of coverage of roll up tonneausystem 12. Receiving channel 97 formed in forward rail member 92receives a bulbous seal 99 that has a first portion 105 disposed inreceiving channel 97, a second D-shaped portion 103 coupled to firstportion 105, and a downwardly biased, curved wiper seal 101 that engagesthe top of front wall 14 to providing a sealing engagement therebetween.Forward rail member 92 is preferably hollow to minimize weight andgenerally rectangular in cross section. At an end opposing receivingchannel 96, forward rail member 92 includes a generally curved portion98. Generally curved portion 98 is adapted to engage a correspondingcurved channel 100 disposed at a forward end of an adjustment supportbracket 102. A recess 104 is formed above generally curved portion 98 onforward rail member 92 to prevent interference with a protruding flange106 extending from adjustment support bracket 102. Accordingly, whenfabric cover 22 is installed above rail support system 24, generallycurved portion 98 of forward rail member 92 may be inserted into curvedchannel 100 in an inclined position and then rotated forward relative tothe vehicle into the illustrated lowered position. During this movement,generally curved portion 98 smoothly rotates with curved channel 100.

As best seen in FIGS. 5 and 6, in order to retain forward rail member 92in this lowered position, a retaining mechanism 108 is provided.Retaining mechanism 108 includes a latch member 110 slidably coupled toforward rail member 92 via a fastener 112, such as a thumb screw, andnut 114, such as an elongated nut or T-nut. Nut 114 is slidably retainedwith a lower C-shaped channel 116 (FIG. 4) extending along an undersideof forward rail member 92. Latch member 110 includes a cantileveredportion 118 adapted to be positioned adjacent an underside of secondhorizontal portion 54 of support bracket 38 to prevent the removal offorward rail member 92 relative to support bracket 38. Retainingmechanism 108 further includes a guide locator 120 having a screw 122retaining a fixed locator 125. It should be understood that guidelocator 120 may be made integral with latch member 110. Lastly, aplurality of steps 123 are disposed along the upper side of latch member110 to provide the necessary spacing of cantilevered portion 118 fromsecond horizontal portion 54.

Referring again to FIGS. 3 and 4, an adjustment mechanism 124 isprovided for engagement with forward rail member 92 to selectivelyposition forward rail member 92 in a further fore or aft position toadjust the tightness of fabric cover 22. This preferred position offorward rail member 92 may vary depending upon installation, age offabric cover 22, environment temperatures and moisture levels, and thelike. To effect such adjustment, adjustment mechanism 124 includesadjustment support bracket 102 that is fixedly coupled via conventionalmethods to second horizontal portion 54 of support bracket 38.Adjustment support bracket 102 is generally box-shaped having protrudingflanges 106 extending from a forward end thereof.

Adjustment support bracket 102 further includes an adjustment bolt 126having a head portion 128 and an engaging portion 130. Head portion 128extends beyond an aft end of adjustment support bracket 102, whileengaging portion 130 engages forward rail member 92. Specifically,engaging portion 130 engages a generally flat portion 132 formed incurved portion 98 to mate with engaging portion 130 of adjustment bolt126. It should be noted that generally flat portion 132 might include alower edge 134 that is held by engaging portion 130 of adjustment bolt126, which aids in retaining forward rail member 92 in a loweredposition.

Adjustment mechanism 124 further includes a nut 136, which is preferablya wing nut having wings that engage interior side surfaces 138 ofadjustment support bracket 102 to prevent nut 136 from rotating relativeto adjustment support bracket 102. A spring 140 extends between nut 136and an interior end surface 142 of adjustment support bracket 102 toproviding a biasing force against nut 136. The length of spring 140 ischosen such that the shrinkage or expansion with temperature of fabriccover 22 will not cause the spring force to vary greatly, thus maintainthe tension in fabric cover 22 nearly constant. Accordingly, asadjustment bolt 126 is driven inward (forward), engaging portion 130 isdriven in contact with generally flat portion 132 of forward rail member92, thereby driving forward rail member 92 forward. Further forwarddisplacement of forward rail member 92, and corresponding fabric cover22, continue until the tension in fabric cover 22 generally equals thebiasing force of spring 140. Therefore, according to the presentarrangement, fabric cover 22 is ensured to remain taut, even duringenvironment temperature and moisture changes and age. However, shouldfurther adjustment of fabric cover 22 be necessary, adjustment bolt 126may simply be further driven forward.

Although, as seen in FIGS. 3 and 4, an adjustment limit 144 may be usedto prevent excessive adjustment of forward rail member 92 in either thefore or aft direction. To this end, adjustment limit 144 includes a bolt146 coupled to a nut 148 disposed in lower channel 116 of forward railmember 92. Bolt 146 downwardly extends and is received with an aperture150 formed in second horizontal portion 54 of support bracket 38. By wayof non-limiting example, it is anticipated that adjustment limit 144would limit the adjustment of forward rail member 92 to within about0.1″ of fore and aft movement. Furthermore, aft movement is limited bythe interface between curved portion 98 and corresponding curved channel100. Adjustment limit 144 prevents forward rail member 92 from slidingforward when fabric cover 22 is rolled up into a forward open positionat the front of cargo box 13. When fabric cover 22 is in the closedposition, the combination of biasing force from spring 140 and inherenttension within fabric cover 22 maintains adjustment limit 144 andforward rail member 92 in proper position.

As best seen in FIG. 3, each support bracket 38 preferably receives apair of bumper members 141 disposed on opposing ends of support bracket38 in a space defined by first downwardly extending portion 52, aportion of first horizontal portion 44, and second downwardly extendingportion 56. Bumper member 141 preferably has a plurality of retainingridges 143 to engage first downwardly extending portion 52, a portion offirst horizontal portion 44, and second downwardly extending portion 56to maintain bumper member 141 within the aforementioned space. Each ofthe pair of bumper members 141 includes a head portion 143 and a baseportion 145. Head portion 143 engages front wall 14 or tailgate 20,while base portion 145 is received in the defined space. Once installed,bumper members 141 engage front wall 14 or tailgate 20 of pickup truck10 and act to align, maintain, and hold support bracket 38 and, thusframe rail assembly 30 in a generally centered fore-aft position.Furthermore, bumper members 141 further serve to properly position seals103 and 161 relative to front wall 14 and tailgate 20, respectively.

Turning now to FIGS. 7-9, a rear latching mechanism 152 will bedescribed in detail. As can be seen in the figures, rear latchingmechanism 152 shares a number of parts with head rail assembly 26. Inparticular, rear-latching mechanism 152 includes the aforementionedforward rail member 92, referenced as rear rail member 92′ hereinafter,and adjustment support bracket 102, referenced as support bracket 102′hereinafter. It should be appreciated that such use of members inmultiple locations within roll up tonneau system 12 provides a number ofmanufacturing and assembly efficiencies. In the interest of brevity,specific reference and explanation of components shared between headrail assembly 26 and rear frame rail assembly 32 will not be discussed.

With particular reference to FIG. 7, rear-latching mechanism 152includes support bracket 102′ being coupled to support bracket 38 viaconventional means, such as fasteners. Rear rail member 92′ receivesattachment member 94 coupled to fabric cover 22 within receiving channel96 formed in rear rail member 92′ to define the rear edge of coverage ofroll up tonneau system 12. Rear latching mechanism 152 still furtherincludes a latching pawl 154. Latching pawl 154 is generally L-shapedhaving a latching hook 156, a trigger/ejector head 158, and a centrallylocated pivot 160. Latching hook 156 is shaped to selectively engage aflange 162 extending within C-shaped lower channel 116. Latching hook156 extends through an aperture 164 formed in second horizontal portion54 of support bracket 38. Aperture 164 is equidistant from an end ofsupport bracket 38 compared to aperture 150 to permit support bracket 38to be used on either a left or right side of cargo box 13.Trigger/ejector head 158 is positioned near a rear end of rear railmember 92′ to permit easy actuation by a user. Trigger/ejector head 158includes a protrusion 166, which may extend through an aperture 168 toengage and translate rear rail member 92′ upward to signal to a userthat rear rail member 92′ has been sufficiently unlatched. It should beunderstood that the length of trigger/ejector head 158 from pivot 160may be increased relative to the length of latching hook 156 from pivot160 for increase mechanical advantage. Rear latching mechanism 152further includes a spring 170 biasing latching hook 156 in an engagedand locked position.

As seen in FIGS. 7-9, as trigger/ejector head 158 is depressed in acounter-clockwise direction, trigger/ejector head 158 pivots upwardabout pivot 160. Such rotation disengages latching hook 156 from flange162. Continued depression of trigger/ejector head 158 causestrigger/ejector head 158 to engage an underside of rear rail member 92′,thereby pivoting rear rail member 92′ about curved portion 98. Rear railmember 92′ may then be removed from support bracket 102′.

Receiving channel 97 formed in rearward rail member 92′ receives abulbous seal 161 that has a first portion 163 slidable disposed inreceiving channel 97, a second D-shaped portion 165 coupled to firstportion 163, and an upwardly inclined wiper seal 167 that engages theside of tail gate 20 to provide a sealing engagement therebetween.Upwardly inclined wiper seal 167 and second portion 165 cooperate toform a channel 169 to collect and direct water outwardly.

Following disengagement of rear latching mechanism 152, rear rail member92′ may be rolled forward to gather fabric cover 22 at a forwardlocation. To this end, it should be appreciated that the generallyhorizontally disposed hook-and-loop fastener system 49, unlike prior artconfigurations, provides a simple “peel-off/on” arrangement in adirection perpendicular to the attachment plane of hook-and-loopfastener system 49. Prior art systems often require additional layers ofvinyl to separate the VELCRO® strips prior to attachment. Additionally,other prior art systems require a shearing action in order to disengagethe VELCRO® strips. These systems require additional complexity toattach and additional force to separate and further limit the life ofthe VELCRO® strips. The “peel-off/on” arrangement of the presentinvention in a direction of perpendicular to the attachment planeprovides improved simplicity in engagement and disengagement ofhook-and-loop fastener system 49 and further improves the useful lifethereof. This gentle action further permits the present invention to useaggressive hook-and-loop fastener systems that do not require them to bepushed into place; however, they are loaded in shear by fabric cover 22yet may be released with a gentle peeling action. It should beappreciated that hook-and-loop fastener system 49 of the presentinvention is disengaged by a simple rolling of fabric cover 22 to itsforward position.

The description of the invention is merely exemplary in nature and,thus, variations that do not depart from the gist of the invention areintended to be within the scope of the invention. Such variations arenot to be regarded as a departure from the spirit and scope of theinvention.

What is claimed is:
 1. A tonneau system for a cargo box of a vehicle,said cargo box having a sidewall, said tonneau system comprising: afirst rail member having a horizontal portion; a second rail memberengagable with said first rail member; a cover spanning said first railmember and said second rail member; and a rail retaining mechanismpositionable in a first position locking said second rail member toprevent said second rail member from being disengaged from said firstrail member and a second position unlocking said second rail member topermit said second rail member to be disengaged from said first railmember, said rail retaining mechanism further urging said second railmember upward in said second position.
 2. The tonneau system accordingto claim 1 wherein said rail retaining mechanism comprises: a lockingpawl; and a spring biasing said locking pawl into said first position.3. A tonneau system for a cargo box of a vehicle, said cargo box havinga sidewall, said tonneau system comprising: a first rail member having ahorizontal portion; a second rail member engagable with said first railmember; a cover spanning said first rail member and said second railmember; and a pivot member pivotally coupled to one of said first railmember and said second rail member, said pivot member being positionablein a first position locking said second rail member to prevent saidsecond rail member from being disengaged from said first rail member anda second position unlocking said second rail member to permit saidsecond rail member to be disengaged from said first rail member; and aprong portion extending from said pivot member, said prong portionengaging the other of said first rail member and said second rail memberand urging said second rail member upward in said second position. 4.The tonneau system according to claim 3, further comprising: a springbiasing said pivot member into said first position.
 5. The tonneausystem according to claim 4 wherein said spring is a leaf spring.